1. Field of the Invention
The present invention relates to a method for producing batches of large numbers of micro particles marked in such a manner as to uniquely identify each batch.
2. The Prior Art
Known methods for producing batches of identically and uniquely marked micro particles are based on a code formed from a plurality of digits, said digits being reproduced on a substrate by means of photo reduction, the substrate then being cut to form a batch of micro particles. The required numerical code is one sequence of multiple sequences of numbers. This results in the particles being excessively large due to the inclusion of irrelevant information.
Current laser marking techniques are based on substrates typically used in the micro-electronics industry to manufacture semi-conductors. These substrates are generally based on wafers of gold, silver or aluminum or of materials such as silicon or silicon dioxide. The particles are formed on the wafer through the deposition and etching processes of silicon micro-machining.
The prior art method for producing micro particles comprise a number of separate processes which increases the cost of production. In particular, separate processes are required for the marking of individual micro particles and the cutting of the substrate from which the micro particles are formed.